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The purpose of this paper is to investigate the interfacial conductivity and corrosion resistance of the Ni–P/Ti₄O₇ composite coating that is deposited on a carbon steel substrate as bipolar plates for proton exchange membrane fuel cells.

The Ni–P/Ti₄O₇ coating was prepared by electroless plating. Scanning electron microscopy, white light interference, energy dispersive spectrometry and X-ray diffraction were used, respectively, to study the surface morphology, chemical composition and phase composition of coated samples. Electrochemical impedance spectroscopy, potentiodynamic and potentiostatic polarization were used to test the electrochemical performance and corrosion behavior. The interfacial contact resistance (ICR) was measured via the standard method.

The surface of the Ni–P/Ti₄O₇ coating is complete and dense and without obvious defects. The electrochemical test results show that the Ni–P/Ti₄O₇ coating provides better corrosion resistance than the Ni–P coating and substrate. Compared with the Ni–P coating, the ICR of the Ni–P/Ti₄O₇ coating is lower by about 82.7%. This is because the coating has more conductive contact points. The more exciting thing is that the ICR of the Ni–P/Ti₄O₇ coating only increases to 12.38 mΩ·cm² after 5 h of polarization.

This paper provides a method for achieving surface modification of metal bipolar plates. Introducing Ti₄O₇ particles in the Ni–P layer reduces the contact resistance before and after polarization while ensuring good corrosion resistance.

The purpose of this paper is to improve the surface electrical conductivity and corrosion resistance of AISI 430 stainless steel (430 SS) as bipolar plates for proton exchange membrane fuel cells (PEMFCs), a protective Nb-modified layer is formed onto stainless steel via the plasma surface diffusion alloying method. The effect of diffusion alloying time on electrochemical behavior and surface conductivity is evaluated.

In this work, the surface electrical conductivity and corrosion resistance of modified specimen are evaluated by the potentiodynamic and potentionstatic polarization tests. Moreover, the hydrophobicity is also investigated by contact angle measurement.

The Nb-modified 430 SS treated by 1.5 h (1.5Nb) presented a lower passivation current density, lower interfacial contact resistance and a higher hydrophobicity than other modified specimens. Moreover, the 1.5 Nb specimen presents a smoother surface than other modified specimens after potentionstatic polarization tests.

The effect of diffusion alloying time on electrochemical behavior, surface conductivity and hydrophobicity of modified specimen is evaluated. The probable anti-corrosion mechanism of Nb-modified specimen in simulated acid PEMFC cathode environment is presented.

The purpose of this study is to improve the surface electrical conductivity and corrosion resistance of AISI430 stainless steel (430 SS) as bipolar plates for direct formic acid fuel cell (DFAFC).

The niobium diffusion layers have been successfully synthesized on 430 SS substrate by the plasma surface diffusion alloying technique under different diffusion alloying time.

The surface morphology of Nb-modified 430 SS prepared under the diffusion alloying time of 2 h is more homogeneous, relatively sleek and compact without surface micropore and other common surface blemishes. The potentiostatic and potentiodynamic polarization measurements manifest that Nb-modified 430 SS prepared under the diffusion alloying time of 2 h enormously ameliorate the corrosion resistance of bare 430 SS compared with other Nb-modified 430 SS samples and its corrosion current density is maintained at −1.4 µA cm⁻² in simulated anodic environment of DFAFC (0.05 M H₂SO₄ + 2 ppm HF + 10 M formic acid at 50 °C).

The effect of diffusion alloying time on the corrosion resistance and surface conductivity of Nb-modified 430 SS has been carefully studied. The Nb-modified 430 SS samples prepared at the diffusion alloying time of 2 h have the best surface electrical conductivity and corrosion resistance in the simulated anodic environment of DFAFC.

The purpose of this paper is to present a novel nanostructured polymer‐metal composite film providing continuous all‐metal thermally conductive pathways, intended to meet future performance requirements on thermal interface materials (TIMs) in microelectronics packaging applications.

Porous polymer structures with a thickness of approximately 100 μm were manufactured using electrospinning technology. Pressure‐assisted infiltration of low‐melting temperature alloy into the porous polymeric carrier resulted in the final composite film. Thermal performance was evaluated using an accurate and improved implementation of the ASTM D5470 standard in combination with an Instron 5548 MicroTester. Finally, a brief comparative study using three current state‐of‐the‐art commercial TIMs were carried out for reference purposes.

Composite films with continuous all‐metal thermally conductive pathways from surface to surface were successfully fabricated. Thermal resistances down to 8.5 K mm² W⁻¹ at 70 μm bond‐line thickness were observed, corresponding to an effective thermal conductivity of 8 W m⁻¹ K⁻¹, at moderate assembly pressures (200‐800 kPa), more than twice the effective thermal conductivity of the commercial reference materials evaluated.

A unique high‐performance nanostructured polymer‐metal composite film for TIM applications with the potential to meet the microelectronics industry's future demands on thermal performance and cost efficiency is presented.

The purpose of this paper is to study the variations of composition and properties of the passive film on 316 L stainless steel surface in 80°C, 0.5 mol L-1 H2SO4 + 2 mg L-1 NaF solution, is helpful to understand the mechanisms of corrosion resistancethe of plated Pd on 316 L ss.

The variations of composition and properties of the passive film on 316 L stainless steel surface in 80°C, 0.5 mol L-1 H2SO4 + 2 mg L-1 NaF solution after connected to Pd electrode were studied with methods of potential monitor, X-ray photoelectron spectroscopy analysis and electrochemical impedance spectrum (EIS) measurement.

By connecting to a Pd electrode, the potential of the SS sample increased from the active region to the passive region. By connecting to the Pd electrode, the contents of Cr, Cr(OH)3 and Fe3O4 in passive film increased obviously. With increased Pd/SS area ratio, the Cr(OH)3 content in passive film increased but the Fe3O4 content changed little. The results show that after connecting to Pd the corrosion resistance of the passive film on 316 L stainless steel increases obviously, which may be attributed to the more compact passive film because of higher Cr, Cr(OH)3 and Fe3O4 contents and less point defects in the film.

The effects and mechanism of Pd on passivation of SS was studied.

This paper aims to evaluate corrosion behavior of bare and PbO₂-coated stainless steel 316L, as prospective candidates for bipolar plates, in simulated proton exchange membrane fuel cell’s (PEMFC’s) environment under operating potentials.

A set of potentiodynamic, as well as potentiostatic, electrochemical experiments was carried out under both anodic and cathodic potentials. Gathered data were analyzed via fast Fourier transform algorithm for further investigation. X-ray diffraction analysis was also used for determining coating characteristics upon completion of electrochemical experiments.

Results revealed that bare SS316L is a better candidate for bipolar plate material under anodic potential, as it is cathodically protected. However, PbO₂-coated SS316L is favorable under cathodic potential, as bare specimen will suffer localized corrosion in the form of pitting.

It would be of interest if all the experiments are carried out in a PEMFC stack.

This research strives to promote the use of electrochemical noise measurement for practical corrosion monitoring of coated bipolar plates in fuel cells.

Improving the corrosion resistance of bipolar plates will expedite commercialization of PEMFCs, which in turn will translate into a substantial reduction in carbon footprint.

This research strives to promote the use of electrochemical noise measurement for practical corrosion monitoring of coated bipolar plates in fuel cells.

This paper aims to investigate the impact of three different flow channel cross sections on the performance of the fuel cell.

A comprehensive three-dimensional polymer electrolyte membrane fuel cell model has been developed, and a set of conservation equations has been solved. The flow is assumed to be steady, fully developed, laminar and isothermal. The investigated cross sections are the commonly used square cross section, the increasingly used trapezoidal cross section and a novel hybrid configuration where the cross section is square at the inlet and trapezoidal at the outlet.

The results show that a slight gain is obtained when using the hybrid configuration and this is because of increased velocity, which improves the supply of the reactant gases to the catalyst layers (CLs) and removes heat and excess water more effectively compared to other configurations. Further, the reduction of the outlet height of the hybrid configuration leads to even better fuel cell performance and this is again because of increased velocity in the flow channel.

The data generated in this study will be highly valuable to engineers interested in studying the effect of fluid cross -sectional shape on fuel cell performance.

This study proposes a novel flow field with a variable cross section. This design can supply a higher amount of reactant gases to the CLs, dissipates heat and remove excess water more effectively.

Polymer-based thermal interface materials (TIMs) are having pump out problem and could be resolved for reliable application. Solid-based interface materials have been suggested and reported. The purpose of this paper is suggesting thin film-based TIM to sustain the light-emiting diode (LED) performance and electronic device miniaturization.

Consequently, ZnO thin film at various thicknesses was prepared by chemical vapour deposition (CVD) method and tested their thermal behaviour using thermal transient analysis as solid TIM for high-power LED.

Low value in total thermal resistance (R_th-tot) was observed for ZnO thin film boundary condition than bare Al boundary condition. The measured interface (ZnO thin film) resistance {(R_th-bhs) thermal resistance of the interface layer (thin film) placed between metal core printed circuit board (MCPCB) board and Al substrates} was nearly equal to Ag paste boundary condition and showed low values for ZnO film prepared at 30 min process time measured at 700 mA. The T_J value of LED mounted on ZnO thin film (prepared at 30 min.) coated Al substrates was measured to be 74.8°C. High value in junction temperature difference (ΔT_J) of about 4.7°C was noticed with 30 min processed ZnO thin film when compared with Al boundary condition. Low correlated colour temperature and high luminous flux values of tested LED were also observed with ZnO thin film boundary condition (processed at 30 min) compared with both Al substrate and Ag paste boundary condition.

Overall, 30 min CVD processed ZnO thin film would be an alternative for commercial TIM to achieve efficient thermal management. This will increase the life span of the LED as the proposed material decreases the T_J values.

The purpose of this paper is to fill the knowledge gap in the microscopic origin of high corrosion resistance in the passivated 316 L stainless steel.

Here, the pitting corrosion potential of the passivated 316 L stainless steel is measured, as well as the non-passivated one. Using the aberration-corrected scanning transmission electron microscopy, the microstructure of the passive film is unambiguously revealed. Combining the electron energy loss spectroscopy with the X-ray photoelectron spectroscopy, the depth profiling analysis is conducted and the variations in composition from the very surface of the passive film to the internal steel are clarified.

By optimizing the passivation treatment process, the authors significantly increase the pitting corrosion potential of the passivated 316 L stainless steel by 300 mV, compared with the non-passivated one. The passive film features a unique amorphous multilayer structure. On the basis of the depth profiling analysis, the origin of the high corrosion resistance achieved is unraveled, in which the redistribution of elements in the multilayer passive film, especially the enrichment of Cr in the topmost layer and Ni at the film-metal interface, prevent the oxidization of the inner iron of the steel.

This study advances understanding of the nature of the passive film from a microscopic view, which can be helpful for the further improvement of the corrosion resistance performance.

This study introduces a model for the multilayer structure of passive films that reveals the reconstitution of the passive films after the opportune passivation treatments. Due to the redistribution of elements caused by passivation, the enrichment of Cr in the outer layer and Ni near the film-metal interface leads to enhance corrosion resistance performance.

The purpose of this paper is to investigate the efficiencies of argon (Ar), oxygen (O₂) and O₂ followed by Ar (O₂→Ar) plasma treatments in terms of contaminant removal and wire bond interfacial adhesion improvement. The aim of this study is to resolve the “lifted ball bond” issue, which is one of the critical reliability checkpoints for light emitting diodes (LEDs) in automotive applications.

Ar, O₂ and O₂→Ar plasma treatments were applied to LED chip bond pad prior to wire bonding process with different treatment durations. Various surface characterization methods and contact angle measurement were then used to characterize the surface properties of these chip bond pads. To validate the improvements of Ar, O₂ and O₂→Ar plasma treatments to the wire bond interfacial adhesion, the chip bond pads were wire bonded and examined with a ball shear test. Moreover, the contact resistance of the wire bond interfaces was also measured by using four-point probe electrical measurements to complement the interfacial adhesion validation.

Surface characterization results show that O₂→Ar plasma treatment was able to remove the contaminant while maintaining relatively low oxygen impurity content on the bond pad surface after the treatment and was more effective as compared with the O₂ and Ar plasma treatments. However, O₂→Ar plasma treatment also simultaneously reduced high-polarity bonds on the chip bond pad, leading to a lower surface free energy than that with the O₂ plasma treatment. Ball shear test and contact resistance results showed that wire bond interfacial adhesion improvement after the O₂→Ar plasma treatment is lower than that with the O₂ plasma treatment, although it has the highest efficiency in surface contaminant removal.

To resolve “lifted ball bond” issue, optimization of plasma gas composition ratios and parameters for respective Ar and O₂ plasma treatments has been widely reported in many literatures; however, the O₂→Ar plasma treatment is still rarely focused. Moreover, the observation that wire bond interfacial adhesion improvement after O₂→Ar plasma treatment is lower than that with the O₂ plasma treatment although it has the highest efficiency in surface contaminant removal also has not been reported on similar studies elsewhere.